Chapter 5:
Control System

By Peter Smid

From CNC Programming Handbook: A Comprehensive Guide to Practical CNC Programming, Third Edition

OVERVIEW

A machine unit equipped with a computerized numerical control system is commonly known as a CNC machine. In an analogy of the machine tool being the body of a CNC machine system, the control unit is its brain, its nerve center. There are no levers, no knobs and no handles on a CNC machine the way they function on conventional milling machines and lathes. All machine speeds, feeds, axes motions and hundreds of other tasks are programmed by a CNC programmer and controlled by a computer that is major part of the CNC unit. To make a program for a CNC machine tool means to make a program for the control system. True, the machine tool is a major consideration as well, but it is the control unit that determines the program format, its structure and its syntax.

In order to fully understand CNC programming process, it is important to understand not only the intricacies of how to machine a part, what tools to select, what speeds and feeds to use, how to setup the job and many other features. It is equally important to know how the computer, the CNC unit, actually works without the need to be an expert in electronics or a computer scientist. Figure 5-1 shows an actual Fanuc control panel.

Figure 5-1: A typical example of a Fanuc control panel - actual layout and features will vary on different models (Fanuc 16M)

Machining centers are machine tools that are used to automatically repeat operations on a workpiece. They are usually numerically controlled. Operations include drilling, reaming, tapping, milling, and boring.